Browsing by Subject "Pacific"
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Item The construction of Honolulu(2014-12) Warren, Nathan David; Kelban, Stuart; Ramirez-Berg, CharlesWithin this report is an examination of the influences, ideas, and historical references that were instrumental in writing the pilot episode of Honolulu. This report will also chronicle the development of the story from its initial inception to its hopeful future. Special attention is given to obstacles in the story that were overcome by unconventional, or counter-intuitive writing measures.Item Great Republic: a historical and archaeological analysis of a Pacific mail steamship(2009-05-15) Roberts, Andrew PhilipIn 1986 the remains of a shipwreck were discovered on Sand Island in the mouth of the Columbia River in the Pacific Northwest. The following year, a team of archaeologists investigated the site in order to determine its original identity. After a series of dives, the team concluded that the wreck was the remains of the Hudson?s Bay Company brig, Isabella, a ship that was lost in that area in 1830. Recent investigations on the shipwreck disproved this identity. The turbulent conditions of the Columbia River have helped researchers by shifting a significant amount of sand overburden away from the vessel, exposing a greater area of the ship. With this new information, the wreck is now believed to be the remains of the wooden side-wheel steamer Great Republic that belonged to the Pacific Mail Steamship Company, rather than Isabella. This thesis investigates the history of Great Republic and its role in American maritime history, as well as its possible archaeological remains at the bottom of the Columbia River. In order to provide a clear and concise story, I begin with the history of the Pacific Mail Steamship Company and its importance in the development of the western coast of the United States. Since Great Republic was integral to the Asian trade of the nineteenth century, the second portion of the thesis is dedicated to Asian-American commercial and political relations during the nineteenth century. Great Republic and its three sister ships are then described and analyzed in detail based on contemporary sources. Finally, the archaeological evidence is assessed beginning with the discovery of the wreck. I detail the investigations and discoveries made on the wreck over the last 20 years. In my conclusions I discuss the importance of Great Republic from a historical standpoint and emphasize its place in American maritime history. I also detail key aspects concerning the wreck that I believe are imperative for future research. Though the remains convincingly appear to be those of Great Republic there are still structural features that need to be analyzed before a positive identification is possible.Item Lead Isotopic Variations of the Pacific and Implications for Paleogene Water Mass Composition(2013-11-13) Subt, CristinaTo understand the effects changes in the meridional overturning circulation (MOC) played on past climate we need to determine where convection occurred. The late Cretaceous and early Paleogene interval (~75 to 35 Ma) was characterized by low meridional temperature gradients. Nd isotopes indicate high-latitude convection in the Pacific Ocean during this interval, with deep waters mixing in the tropical Pacific. Here we investigate the evolution of the Pb isotopic composition of water masses in the Pacific to constrain variability in weathering inputs into the inferred convection regions from ~75 to 35 Ma. We generated ^(206),^(207),^(208)Pb/^(204)Pb isotope records for North Pacific DSDP and ODP Sites 192, 464, and 883, and South Pacific DSDP Sites 323, 463, and 596. South Pacific deep waters increasing in contributions. Pb composition in the subtropical South Pacific also suggests a stronger influence of dust dissolution whereas the Nd composition was dominated by water mass composition. North Pacific Pb values may also have reflected shifting sources during the EECO. The Pb and Nd composition at Site 883 shows a short radiogenic excursion in Pb values ~40 Ma, possibly cased by a short period of strengthened North Pacific Deep Water (NPDW) influence on the isotopic composition during the Mid-Eocene Climatic Optimum (MECO). ^(206)Pb/2^(04)Pb trends differ from ^(207),^(208)Pb/^(204)Pb values, which typically show similar trends to each other?resulting from the mixing of multiple Pb sources. North Pacific sites typically exhibit relatively lower Pb compositions than South Pacific, and evidence from detrital analyses suggests sources of Pb to North Pacific sites received strong contributions of continental dust. Pb and Nd are coupled in North Pacific sites between ~62 and 50 Ma, as well as in the Southern Ocean throughout the study period, indicating the Pb composition in this region was influenced by the composition of advected deep water masses. North Pacific sites also show decoupling of Pb and Nd ~50 Ma, during the Early Eocene Climatic Optimum (EECO), which may be indicative of more distalItem Processing innovations to improve PP precursor analysis and increase frequency content of studies in the Mid-Pacific(2012-08) Duncan, Gregory; Gurrola, Harold; Yoshinobu, Aaron S.; Zhou, Hua-weiPP wave data is gathered for bouncepoints primarily in the Pacific Ocean using earthquakes of magnitude 6.2 or greater occurring along the Mariana/Izu-Bonin subduction region, as well as Tonga and the Indonesia plate. The data is composed of midpoints that fall in the Mid-Pacific with a particular concentration under Hawaii. Data is recorded in seven different seismic arrays in the United States but is mainly from the Transportable Array (TA) and USArray (US) stations. The data underwent rigorous cleaning before final analysis. On top of the normal aspects, such as rotating and cutting of data, we utilized a beaming technique on both sides. On the receiver end, it’s simply called beamforming; on the source end it is called simultaneous iterative deconvolution (SID). This cleaning technique is utilized to see how well PP waves can be used in long offset mantle discontinuity studies. Of particular interest to our study are the 410, 520, and 660 discontinuities, which react differently to thermal anomalies such as subducting slabs or hotspots. The dataset had very good ray coverage around Hawaii but dispersed a bit on the outskirts of the dataset, particularly in the southern region. The double-beaming technique is applied to the PP data. Frequency content is increased to as high as 1 Hz while still getting legitimate results. SID was able to get frequencies as high as 4 Hz. 1 Hz is significantly higher than frequencies typically used in these types of studies, which is around .1 Hz. Though frequency was attempted as high as 8 Hz, it was found that PP waves had too little of these upper frequencies. The high frequencies were wiped out during waterlevel deconvolution, a method used to help stabilize the data by filling spectral nulls in frequency with white noise. The improved PP method allows interpretation of both cubes around Hawaii as well as a long line that intersects the majority of the data. Overall, the Tahiti and Hawaii hotspots are analyzed, as well as the subduction zone at the Southern Explorer Ridge (SEXP). It is found that in the Tahiti region, the 410 and 520 both deepen significantly due to the high thermal anomalies associated with hotspots. Hawaii, however, does not display these deepened horizons. This implies thermal anomalies associated with the Tahiti hotspot could be thermally stronger than the Hawaii hotspot. A double 520 can be seen in regions around Hawaii in datasets that have not been ocean corrected. Discontinuities seem stronger in non-ocean-corrected datasets overall, probably due to receiver function familiarity. Farther north, we anticipate a deepening of the 410 associated with the data line moving to continental crust, but it is difficult to decipher. We also look for a rise in this region for the subducting slab, but it is difficult to see due to resolution on the extremities of the dataset. The 410 may rise at this point, but it could possibly be an inaccurate interpretation.